24-11-2012, 02:27 PM
Processing and Characterization of Piezoelectric Materials into MicroElectroMechanical Systems
Piezoelectric Materials in MEMS (Wang Weiqiang).ppt (Size: 1.27 MB / Downloads: 121)
Introduction
MicroElectroMechanical Systems (MEMS) denote systems that include one
or more small microstructures (sub- μm to mm) that often are fabricated using
a technology μnamed micromachining, and materials,that originates partly from
the semiconductor industry’s processes and partly from precision mechanics.
Piezoelectric-based MEMS are generally attractive due to their high sensitivity
and low electrical noise in sensing applications and high-force output in
actuation applications
Advantages
Fine scale and high aspect ratio. (rods 95 μm in diameter and 400 μm in height using lost plastic mold method. )
Advantages of Si
high melting point (1440°C) and high strength
Si mold can be used as a part of the device
Si micromachining techniques have been well developed
Problems
X-ray diffraction (XRD) analyses shows
that perovskite PZT was the major phase,
at the same time, certain amounts of
undesired pyrochlore-type PZT phase
was also observed.
Conclusion
Piezoelectric materials have been successfully applied in a variety of MEMS applications. The development of fabrication methods such as PZT structural micro-machining, low-stress silicon nitride deposition, and solution deposition of piezoelectric thin films has been essential. The MEMS applications described here compare favorably with other MEMS approaches based on commonly used electrostatic actuation. The continued promise for piezoelectric MEMS is attractive.